The goal of the proposed research is a behavior genetic analysis of existing data on components of the aging process. Newly developed methods for analyzing cross-sequential twin data will be applied to measures of functional aging. The Swedish Adoption/Twin Study of Aging (SATSA) incorporates longitudinal follow-up of an originally cross- sectional sample of reared-apart and reared-together monozygotic and dizygotic twins ranging in age from 41 to 88 years. The SATSA archive includes measures of objective health, subjective health, motor abilities, activities of daily living, mobility, neurology, nutrition, anthropometry, mental status, environmental variables, psychosocial variables, personality, and cognitive abilities. Cross-sequential twin analysis will provide the foundation for addressing four research questions. First, do the components of functional age identified in an American sample generalize to a Swedish sample? Second, what is the relative influence of genetic and environmental factors on the components of functional age? Third, to what extent do identified components of functional age represent true age changes as opposed to cohort differences? Fourth, do genetic and environmental influences on components of functional aging demonstrate age changes or cohort effects? Funds are requested to support the principle investigator during a 6- month stay in Stockholm to collaborate with the director of SATSA.